Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
  • B24B3/00—Sharpening cutting edges, e.g. of tools; Accessories therefor, e.g. for holding the tools
  • B24B3/36—Sharpening cutting edges, e.g. of tools; Accessories therefor, e.g. for holding the tools of cutting blades
  • B24B3/54—Sharpening cutting edges, e.g. of tools; Accessories therefor, e.g. for holding the tools of cutting blades of hand or table knives

Definitions

• the face of the hunting knife is laid on a planar angle guide surface and held there by hand, by a magnet or a spring. Because of the complex geometric design of the face of hunting and certain Asian knife blades the positioning of these style blades on such angle guides is unstable and ambiguous, consequently precise angular control of the facets being ground at the knife edge is seriously compromised.
• An object of this invention is to provide a sharpener capable of precision sharpening hunting style knives and various Asian knives.
• Figure 1 is a side elevational view, partly in section, of a prior art sharpener
• Figures 2-3 are side elevational views of typical hunting knives
• Figures 2 A and 3 A are cross-sectional views of the hunting knives shown in Figures 2-3 taken along the lines 2A-2A and 3A-3 A, respectively;
• Figure 4 is a cross-sectional view of a hunting knife
• Figures 5-6 are side elevational views, partly in section, of prior art sharpeners for sharpening hunting knives;
• Figure 7 is an enlarged cross-sectional view of a hunting knife
• Figure 8 is a side elevational cross-sectional view of a portion of a sharpener in accordance with this invention
• FIG. 9 is a side elevational view of yet another sharpener in accordance with this invention.
• FIG 10 is another variation of the application of this invention.
• Figure 1 illustrates the conventional prior art means of controlling the position of a knife blade 1 as its edge facet is placed into contact with a rotating abrasive-covered disk 3.
• the abrasive disk mounted on shaft 4 is motor driven. The motor is not shown.
• the conventional knife blade 1 is positioned by hand against the inside surface plane of the knife guide 5 and is pressed against that surface by a conventional inverted U shaped spring 13 that has a large flat arm 17 that presses against the right flat face of a conventional knife 1.
• This type of knife holding spring conforms well to the flat face of a conventional knife blade and presses the knife's back face into good alignment with the contacting planar surface of the guide 5.
• a knife whose faces are planar and parallel is securely positioned between arm 17 of the spring 13 and the contacting flat surface of guide 5.
• a conventional type spring such as spring 13 works well insuring precise angular positioning of the knife edge facet against the rotating abrasive disk 3.
• a pair of abrasive covered disks is commonly used as shown so that the knife is sharpened first by placing it alternatingly in the left slot and then in the right slot to grind a facet on each side of the edge.
• a metal compression spring 29 is placed between the abrasive disks (which are slidable along shaft 4 but restrained by spring 29) to press and position the disks on the shaft 4 against positioning stop pins 11 in the absence of a blade.
• the knife edge 19 contacts the rotating abrasive disk and the disk is slidingly displaced along shaft 4 by the edge facet along the rotating shaft against the force of the spring 29.
• the blade face is manually slid down the guiding surface of guide 5, its edge contacts and then displaces the rotating disk laterally as the knife edge continues to move down until it contacts a stop bar 21.
• the blade adjacent to its edge then is being pressed securely by spring 29 against the long portion of the guide plane.
• the knife holding spring 13 presses the flat faced blade of Figure 1 against the upper section of the guide surface of guide 5 and the blade is very stable as its edge is being sharpened.
• FIG. 1 A The cross section A-A of these blades is shown in adjacent Figures 2 A and 3 A. These commonly show hollow ground features 36 on the lower sections 31 of the blade face adjacent to the edge but the upper sections 34 of the blade faces adjacent to the blade backs 33 are generally planar and parallel to each other.
• FIG. 4 The cross-section of a typical hunting knife is shown enlarged in Figure 4.
• the back 33 (spline) of the blade 2 can be seen to be very thick and the upper section of the faces 34 adjacent the back is flat and parallel.
• the lower hollow ground sections areas 31 adjacent the edge are concave in shape. While the upper sections of the faces are parallel to the center line of the blade thickness, the lower concave sections lie within a plane that can be considered to be at an angle C relative to that center line. Angle C is commonly 5 - 6° to the thickness center line on hunting knives.
• FIG. 5 shows the cross section of hunting blade 2 (of Figure 2 A and 4) aligned with the upper section of the face 34 against the surface of guiding member 5.
• Figure 6 shows the same blade 2 with the lower section of its face 31 aligned against the same inner planer surface of guide 5.
• the blade will align either with upper section 34 of the face or with the lower section 31 of the face established by the tapered hollow ground area.
• the blade face sections 34 and 31 ( Figure 5) meet at the point or line identified as X and the instability can act in a see-saw pivoting fashion about line X. See Figures 4-7. This action is aggravated when the blade height (width) is non-uniform along the blade length.
• a substantially different and unique knife holding spring 41 (Figure 8) can eliminate the problem of angular instability and insure precise alignment of the hunting blades and sashimi blades as they are moved slidingly along a planer knife guide. Pressure by the knife holding spring must be applied to the lower section of that blade face above the edges in order to press the lower section of the opposing blade face into alignment with the angular guide plane. It is preferable that the spring force be applied directly to the concave section 31 ( Figures A, 7 and 8) that is adjacent to the blade edge facet.
• a force applied at that location acts to press that lower planar or concave section of the blade adjacent the edge securely against the surface of the planar knife guide in concert with the sharpening force applied to the facet being sharpened by the spring 29 that presses the abrasive surfaced disk against the edge as it is sharpened.
• the force being applied by the novel knife holding spring 41 must be located to contact the lowermost portion of the planar area or somewhere on the concave area and optimally relatively close to and preferably below the pivoting line X as shown in Figure 8.
• the pressure can be in part slightly above the line X, but not so much above line X and not with sufficient pressure to cause the blade to become unstable and pivot about line X as it overcomes the counter force applied to the edge by spring 29.
• Spring 41 ideally, should be designed to contact the lower planar or concave section of the knife face at several positions within that section including close to the edge to help the user hold the blade securely and overcome any tendency of the user to disturb the good contact of the lower section of the blade face that is in contact with the angle guiding surface. Contact within the lower section also helps hold conventional planar faced smaller knives in position when one wishes to sharpen such blades, as explained below.
• Figure 8 shows a spring 41 designed primarily for the hunting and Asian blades where the upper portion 39 of the spring arm is sufficiently flexible that the upper portion will bend sufficiently to allow a thick blade to be inserted between the spring's elbow 43 and the surface of guide 5. This allows the elbow 43 to remain in contact with the blade and to apply the full spring force to the blade at, near or below the line X to insure stability of such larger blades.
• the spring's elbow is optimally located approximately 5/8 to 3/4 inch above the blade edge to hold the larger sporting blades as they are sharpened.
• a stop bar 21, ( Figures 8 and 9) is commonly used to control the vertical location of the blade edge as it is being sharpened.
• the upper portion 39a and 39b of the spring above the elbow extends in practice approximately a similar distance - about 5/8 to 3/4 inch above the elbow and thai section is preferably designed to provide clearance as larger knives are inserted and to insure that this portion of the spring above the elbow does not contact the face of the fully inserted blade significantly above line X.
• the sharpening spring 29 that applies its force to the sharpening disks and in turn to the blade facet acts generally in consort with the knife spring 41a in a direction that helps insure that the lower blade section is held in good contact with the surface of guide 5. If the elbow contacts the blade significantly above line X there will be a see-saw type competition of forces between the sharpening spring 29 and the knife holding spring 41a. The resultant of the spring forces and their leverages involved must give a net larger leverage force below line X to insure the stabilizing of such large blades. In this situation the balance of forces must act to hold the lower section of the blade in good alignment with the planer knife guide and in no case do you want to create a balance of forces that cause alignment of the upper section of the rear blade face against the knife guide.
• FIG. 9 The design of a holding spring 41a that has proven effective with both smaller blades and a wide range of hunting and specialized one sided Japanese knives is shown in Figure 9. That figure shows the structure of this novel spring with a cut away of the left knife guide structure in order to illustrate the relaxed unrestrained shape of the spring arms.
• the right spring arm is shown in its working position when restrained by the knife guide with a small knife blade 6 in place for sharpening.
• the lower portion 45b of the right spring arm presses against the face of the blade as shown. Because the faces of the smaller blade 6 are flat the lower portion 45b can press against any area on that blade face and hold the opposite face of the blade in intimate contact with the surface of guide 5.
• the knife holding spring 41 and 41a is of generally inverted U ⁇ shape having an upper bight portion which merges into downwardly extending arms. Each arm has an elbow 43. Each arm then continues downwardly beyond the elbow to a free outer end. The spacing between the elbows is greater than the width of the bight portion.
• This knife guiding concept is possible including the one shown in Figure 10.
• the spring design can be very much the same as discussed earlier but it is shown here in another application where the abrasive sharpening element is on that side of the blade opposite the pressing arm of the knife holding spring.
• the spring is shown on one side of the blade and the abrasive sharpening element is contacting the facet on the opposite side of the blade as shown.
• This dual arm U shaped spring of Figure 10 can be supported as shown for example or supported from a cover or other overhead structure (not shown) above the sharpening stages.
• the spring can be either a dual arm or a single arm design.
• a dual arm design can be supported in such a manner ( Figure 8) that each of the spring arms serve as a knife guide spring for one of the two sharpening elements in the same sharpening stage or it can be supported between sharpening stages and each of the arms serve as a knife guide spring for a sharpening element in different sharpening stages.
• the arrangement of Figure 9 might prove more applicable between sharpening stages and it could be supported either from above or below the top connecting section of the arms.
• the spring arm 47 press against the lower section 31 of the blade 2 so that the blades opposite lower section is pressed into intimate alignment with the surface of the knife guide 5.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Finish Polishing, Edge Sharpening, And Grinding By Specific Grinding Devices (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

Country Status (6)

Cited By (1)

Families Citing this family (32)

Citations (2)

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• 2008
  • 2008-04-15 WO PCT/US2008/060299 patent/WO2008130900A1/en active Application Filing
  • 2008-04-15 CN CN200880016460.6A patent/CN101678525B/zh active Active
  • 2008-04-15 JP JP2010504179A patent/JP5457334B2/ja active Active
  • 2008-04-15 EP EP08745822.0A patent/EP2146819B1/en active Active
  • 2008-04-15 US US12/103,007 patent/US7686676B2/en active Active
• 2010
  • 2010-08-20 HK HK10107993.0A patent/HK1141490A1/xx not_active IP Right Cessation

Patent Citations (2)

Non-Patent Citations (1)

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